Do you think your system would be compatible with MOLOG over SICStus Prolog?
I would like to let my system modular until the point to support non-classical logics (as MOLOG states)
And I imagined them object-oriented.

From the first URL you give, you find a PDF stating "This system is written in Prolog as a module for Prolog." If you download the 2.0 version, the README file states "The MProlog module can be loaded by ...". But, if you look into the code, there's no module definition! The code seems to be dumped in the "user" pseudo-module upon consulting. There are also definitions for operators and predicates that will conflict with both Logtalk and Prolog built-in predicates and operators. So, your first task, if you want to use code, would be to encapsulate it in a true module/object or set of modules/objects and solve all the conflicts.